The manufacture of lamps having a press through which a metal foil, typically a molybdenum foil, extends to form an electrical conductor is difficult since problems arise in connection with alignment and directing the current conductors which lead from the outside of the lamp bulbs towards the inside thereof, and more particularly to insure proper alignment of the internal conductors while the lamp press is being formed. The sealing foils usually are very thin--frequently less than 0.05 mm thickness, are tiny, and thus have practically no stiffness. Alignment of external current conductors can be transferred towards the inner current conductors only to a limited degree, and, hence, the lamp elements which will be placed within the bulb are also difficult to keep in alignment. Some constructions have been used in which support elements are employed which are coupled to lamp parts and are supported on or support against the inner wall of the bulb. Such arrangements are expensive, difficult to make, and cause shadow effects in the light output from the lamp, which is undesirable.
It has previously been proposed to stiffen the metal foils used in a discharge lamp by folding the edges of the sealing foils in zig-zag formation, so that, in cross section, they will have generally Z-shape (see U.S. Pat. No. 4,254,356).
The corrugation or Z-folding of the foil is intended to increase the stiffness thereof and to thus insure better alignment of the electrodes of the discharge lamp. For hermetic sealing, the subassembly is introduced into the neck of the bulb, and the neck is then heated in the region of the sealing foil until it collapses. This arrangement permits a somewhat improved centering due to the stiffening of the sealing foil; it does not, however, use a lamp press with the attendant advantages of a press seal.